A copy of Edmund Scientific's catalog appeared in our mailbox today and while reading through it I noticed the very unscientific use of units. A hodgepodge of US customary and metric (some with conversions, most without). Bizarrely, they also do a few conversions or sizes commonly done in metric (even here in the USA) such as 35mm screens listed as 1.4 inches.
Here's a few examples:
Telescopes
There's a table with:
- Aperture: millimeters mostly with a conversion
- Focal Length: millimeters mostly with a conversion
- Eyepieces: millimeters
- Weight: pounds
The detail for the telescopes gives:
- Primary Mirror: inches (with fractions) with conversion to millimeters
- Eyepieces: millimeters but the barrel is in inches (with fractions)
- Body: inches
Weather Balloons
The diameter is in feet, but it's an obvious conversion from meters.
Weather Monitors
Some have conversions, others don't. Everything that has metric the customary is obviously converted from the metric (e.g. 1,000m into 23,000 feet).
Monocular
This one has a conversion involving a 3.1 magnification calculating 1,000 yards to 583 feet (note, 1,000 yards divided by 3.1 is 968 feet).
Reciprocating Submersible Pump
- Flow height: inches
- Capacity: pints per minute
- Tubing: inches and fractions of an inch
- Suction height: centimeters
- Pressure height: centimeters
- Length and Diameter: inches (with decimals of an inch)
- Weight: grams
Marble Run
- Central tower: feet
- Track: yards
- Marble sizes: millimeters
Gyroscope
- Diameter: inches with fractions
- Rotor: centimeters
So, we have a mess of units where they can't keep to using a system in a consistent manner (i.e. fractions of an inch versus decimals of an inch) let alone the same system in any one paragraph.
Given that one of the aims of science is to be able to relate things to each other, how are our children supposed to relate any of the parts in a toy to others (let's not discuss the fun one might have if you could relate measurements between toys)? This seems far from scientific.
Don't our children have better things to learn than an endless array of useless conversions?
